Process for the manufacture of chamois tanned leather



Patented Jan. 31,1928.

R, ESSLINGBN-ON-THE-NEGKAB, GERMANY.

PROCESS FOR T583 MANUFACTURE OI GHAIOIS TANNED LEATHER.

10 Drawing. Application iiled September 88, 1926; serial No. 188,328,and in Germany August 89, me.

The invention relates to a chamois tanning recess, in accordancewithlwhich the skin 15 depilated in the usual way, and is then tannedwith a mixture of extracted egg oil and an aqueous solution offormaldehyde. It is preferred to depilate the skins by the well knownmethod of us ng lime, followed by bating, but any other appropriatedepilating operation (as for instance sweating) may be used. It is truethat egg yolks are used in the tanning of glac leat er and egg oil whichhas been extracted 1s used in the tanning of Danish leather. It may herebe noted that egg yolks, andegg oil which has not been extracted,contain lecithin albumen. Extracted egg oil comes from dried egg yolk,extracted with ether, and it contains no lecithin albumen. Neither theuse of egg yolks nor the use of extracted I) egg oil, mentioned above asheretofore proer. 0 new process on the con 'elds a soft, pliant, velvetyand white w cather without bleaching in the sun on grass.

as The leather produced by the new procem can also be dyed any colourbetter and more uiriiformly than leather tanned with train 0 In'the newprocess the. operations are as no follows:

'lheakinisfulledina'fullingmi with eggoiltowhichisadded btoflpercent'posed reduces chamois tanned Wash l th- Th at the same time freed frosofteningof a 40% solution of formaldehyde accord-- ing tothe thicknessof the skin. When the skin has been properly tanned in the egg oil 35there is no risk that the amount of water contained in the formaldehydemoisten the skin again as water is unable to penetrate the fibres of theskin which "are completely saturated with the egg. oil. The 0formaldehyde which is soluble megsgkgil will however penetrate thefibres of the owing to the vigorous fulling and as is well known willmake'it waterproof by its action and the chemical change which takesplace, a

thatistosaywilltanit.

. The whole of the operation consisting m repeatedly .fulling thoroughlywith the said egg oil containing formaldehyde and hanging up the skintwice, takes at the very most from two to four da s according to j thethickneseof the skin. e skin after be well wrung out can be washed asusual an The operations of drying and are those commonly employed.

I claim A process for producing chamois tanned leather, comprisingdegilating the'skin in the usual manner, and en the thus ll treated skinwith a mixture ofextracted egg oil and aqueous formaldehyde solution.

